Experimental procedure. At time 0, animals were anesthetized, tracheostomized, and connected to the ventilator. Through the carotid artery, fluid and anesthesia were administered at a rate of 40 ml/kg/h for 30 min after the initiation of ventilation. At 30 min, fluid infusion rate changed to 15 ml/kg/h in all groups, and ventilator settings were changed as indicated in groups allocated to high VT ventilation. The Tpl2 inhibitor-treated groups received an intraperitoneal injection of Tpl2 inhibitor (thick black arrow), either 5 min prior to the initiation of high VT ventilation (pretreatment) or 30 min after high VT ventilation (posttreatment).